Testosterone Total, and Free Testosterone

Sample

1. It is done in the serum.
2. Can use heparinized plasma.
3. 24 hours of the urine sample.
4. Separate the serum immediately, if kept for a longer period (more than 6 hours),  may get false high values.
5. The sample is stable at 1 to 4 °C for one week.
6. Free Testosterone is stable for 1 to 2 days at 4 °C.
7. At -20 °C sample is stable for 6 months.

Precautions

1. Separate serum from the cells within 6 hours otherwise there is the false elevation of the value.
2. The level is high in adults in the AM sample and 25% lower in the evening sample.
3. In females lower values with increase 1 to 2 days mid-cycle.
4. High values after the exercise.
5. Value is decreased after the overload with glucose.
6. There is a slow progressive decrease after the age of 50 years.

Purpose of the test (Indications)

1. This test is done in male to assess the:
   1. Hypogonadism.
   2. Cryptorchidism.
   3. Impotence.
   4. Pituitary gonadotropic function.
   5. Infertility.
   6. Precocious puberty.
   7. Tumor marker for the testicular tumors.
2. In the female this test is done to assess:
   1. Hirsutism and virilizing syndrome.
   2. Ambiguous sex character.
   3. Precocious puberty.
   4. Tumor marker for ovarian tumors.
   5. Maybe part of the fertility workup of the chronic anovulatory cycle due to the polycystic ovary.

Pathophysiology

1. Testosterone is the main androgen secreted by the testes and its production increases by puberty.
   1. Women only produce 5 to 10% of the testosterone as much produced by the male.
2. Androgenic hormone includes :
   1. Dehydroepiandrosterone (DHEA).
   2. Androsterone.
   3. Testosterone.
3. The adrenal gland produces   DHEA, Cortisol, Aldosterone, and Testosterone.
   

   Adrenal gland Androgens

4. Testes produce DHEA.
5. Ovaries produce DHEA.
6. DHEA is a precursor of the Androstenedione precursor of Testosterone + estrogen.

6. Testosterone is responsible for the development of male secondary characters.
7. Testosterone secreted : 
   1. In men by:
      1. Adrenal glands produce 2/3.
      2. Testes produce 1/3.
   2. In female by:
      1. Adrenal glands. Almost all from the adrenal glands.
      2. Ovaries.

8. The pituitary gland produces  LH in males and FSH in females.
   1. LH  stimulates the Leydig cells to produce  Testosterone.
   2. FSH  Stimulates Sertoli cell to help in spermatogenesis.

9. Testosterone stimulates spermatogenesis and secondary sex character.
   1. Testosterone Increased production :
      1. In Male produces premature puberty.
      2. In female produce masculinity (manifested by amenorrhea, and excessive growth of body hairs).
10. Testosterone exists in two forms in the serum.
    1. In males:
       1. Abound fraction consists of :
          1. 60 to 65 % strongly bound to sex hormone-binding globulin.
          2. The rest most of it is loosely bound to albumin.
    2. In females:
       1. Abound fraction consists of:
          1. 1% is free.
          2. 80% bound to sex hormone-binding globulin (SHBD).
          3. 19% bound to albumin.
    3. The free fraction is 2% which is unbound to sex hormone globulin and albumin.
11. Total testosterone = Bound fraction + Free fraction.
    1. Free fraction is the Active form.

12. Testosterone has fluctuation in the level.:
    12. In the male, there is a peak level early in the morning.
    13. In the female, there is cyclic elevation 1 to 2 days around mid-cycle.
13. Serum level of testosterone :
    1. in male infants :
       1. By 2 weeks = around 25 ng/dL.
       2. BY 2 months = around 275 ng/dL.
    2. In female infants :
       1. By 2 weeks = around 25 ng/dL.
       2. By 2 months = Value decreases and remains low throughout early childhood.
14. Testosterone is made by :
    1. In males mainly by the Leydig cells which is almost 95 % of the total.
    1. In female :
       1. About 50 % is made by the conversion of DHEA in the fatty tissue.
       2. 30 % conversion of DHEA in the adrenal glands.
       3. 20 % made directly by the ovaries.
15. Testosterone is metabolized in the liver and the main metabolites are:
    1. Androsterone.
    2. DHT (dihydrotestosterone).
       1. These are further metabolized into androstenedione and etiocholanelone.
       2. End metabolites are excreted through the kidneys.
16. A testosterone stimulation test is done for hypogonadism. This stimulation can be done by giving clomiphene, and HCG.
17. The main metabolites of adrenal, testicular, and ovarian hormones are secreted through kidneys as 17-ketosteroids.

NORMAL

Source 1

Testosterone Free

Age	pg/mL
	Male	Female
Cord	5 to 22	4 to 16
Newborn (1 to 15 days)	1.5 to 31.0	0.5 to 2.5
1 to 3 month	3.3 to 8.0	0.1 to 1.3
3 to5 month	0.7 to 14.0	0.3 to 1.1
5 to 7 month	0.4 to 4.8	0.2 to 0.6
Children
6 to 9 year	0.1 to 3.2	0.1 to 0.9
10 to 11 year	0.6 to 5.7	1.0 to 5.2
12 to 14 year	1.4 to 156	1.0 to 5.2
15 to 17 year	80 to 159	1.0 to 5.2
Adult	50 to 110	1.0 to 8.5

• To convert into SI units x 3.47 = pmol/L

Testosterone Total (blood)

Age	ng/dL
	Male	Female
Cord	13 to 55	5 to 45
Premature	37 to 198	5 to 22
Newborn	75 to 400	20 to 64
1 to 5 month	1 to 177	1 to 5
6 to 11 month	2 to 7	2 to 5
Children
1 to 5 year	2 to 25	2 to 10
6 to 9 year	3 to 30	2 to 20
Puberty Tanner stage
1	2 to 23	2 to 10
2	5 to 70	5 to 30
3	15 to 280	10 to 30
4	105 to545	15 to 40
5	265 to 800	10 to 40
Adult	280 to 1100	15 to 70
Pregnancy		3 to 4 x adult level
Postmenopausal		8 to 35

1. To convert into SI unit x 0.0347 = nmol/L

Urine

• 20 to 50 years
• Male   = 50 to 135 µg/day
• Female = 2 to 12 µg/day
  • >50 years
    • Male = 40 to 60 µg/day
    • Female = 2 to 8 µg/day

Source 2

Total testosterone

• Men = 3 to 10 ng/mL
• Women = <1 ng/mL
• Prepubertal boys and girls = 0.05 to 0.2 ng/mL

Source 4

Free testosterone

• Men = 50 to 210 pg/mL.
• Women = 1.0 to 8.5 pg/mL.
• Children:
  • Boy = 0.1 to 3.2 pg/mL.
  • Children Girl = 0.1 to 0.9 pg/mL.
• Puberty:
  • Boy = 1.4 to 156 pg/mL.
  • Puberty Girls = 1.0 to 5.2 pg/ml.

Total testosterone

• Men = 270 to 1070 ng/dL.
• Women = 15 to 70 ng/dL.
• Postmenopausal women = 8 to 35 ng/dL.
• Pregnant women = 3 to 4 ng/dL

Increased values of Total Testosterone is seen in:

1. Male
   1. hyperthyroidism.
   2. Adrenal tumors.
   3. Adrenal Hyperplasia.
   4. Hypothalamic tumor, Pinealoma.
   5. Viral encephalitis.
   6. Testicular or extragonadal tumors where Leydig cells produce testosterone.
   7. Testosterone resistance syndrome.
2. Female
   1. Adrenal neoplasm.
   2. Hilar cell tumor.
   3. Idiopathic Hirsutism.
   4. Trophoblastic disease during pregnancy
   5. Ovarian tumors
   6. Polycystic ovary.

Decreased Total testosterone value is seen  in Male:

1. Klinefelter syndrome.
2. Pituitary failure leading to hypogonadism.
3. Hypopituitarism may be primary or secondary.
4. Orchiectomy.
5. Delayed puberty.
6. Down syndrome (trisomy 21).
7. Cirrhosis.
8. Cryptorchidism due to undescended testes.

Increased Free Testosterone is seen in Female:

1. Hirsutism.
2. Virilization.
3. polycystic ovaries.

Decreased Free Testosterone is seen in Male:

1. Hypogonadism.
2. old age.

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